Thread wiper and thread end holder for sewing machines



June 10, 1969 R. J. ROSS 3,448,708

THREAD WIPER AND THREAD END HOLDER FOR SEWING MACHINES Filed June 25, 1967 Sheet 4 of s INVENTOR. Roger J. Ross V/"HOSS June 10, 1969 J, oss 3,448,708

THREAD WIPER AND THREAD END HOLDER FOR SEWING MACHINES Filed June 23, 1967 Sheet 5 of 3 Roger J. Rbss Witness $241 4! 7 1. I )ATTORNEY June 10, 1969 R. J. ROSS 3,448,708

THREAD WIPER AND THREAD END HOLDER FOR SEWING MACHINES Filed'June 25, 1967 Sheet 3 0123 Fig.5.

CONTROL 'SYSTEM L a-s' CAP-2 INVENTOR. Saba Roger J. Ross United States Patent 3,448,708 THREAD WIPER AND THREAD END HOLDER FOR SEWING MACHINES Roger J. Ross, Dover, N.J., assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed June 23, 1067, Ser. No. 648,385

Int. Cl. Db 53/00, 3/00 U.S. Cl. 112253 3 Claims ABSTRACT OF THE DISCLOSURE Summary of the invention This invention relates to devices for wiping a sewing machine needle thread from the work at the completion of a stitching operation and for detaining the thread end from entanglement in the beginning of the succeeding stitching operation.

It is an object of this invention to provide a needle thread wiper and thread end holder which will not hinder the operators view of the stitching area nor detract from the space available near the stitching point for operator manipulation of a work fabric.

Another object of this invention is to provide a needle thread wiper and thread end holder which operates to engage and manipulate a thread end-with that degree of certainty which will insure consistent withdrawal of thread ends from the work and detention of the thread ends out of entanglement with the beginning of the succeeding line of stitches.

Still another object of this invention is to provide a needle thread wiper which cannot damage the needle nor be damaged by the needle in the event of accidental premature operation of the thread wiper.

Description of the drawings With the above and additional objects and advantages in view as will hereinafter appear, this invention comprises the devices, combinations, and arrangements of parts hereinafter described and illustrated in the accompanying drawings of a preferred embodiment in which:

FIG. 1 represents a perspective view of a portion of a sewing machine having the present invention applied there- [0,

FIG. 2 represents a perspective view of the sewing machine presser-foot and thread carrying needles and portions of the thread wipers of this invention, showing the thread wipers extended to engage the threads,

FIG. 3 represents a perspective view similar to FIG. 2 but showing the thread wipers retracted into thread end holding position and with one of the thread wiper tubes broken partly away to illustrate the position of the thread wiper therein,

FIG. 4 is an exploded perspective view illustrating in detail the construction of the thread wiper of FIG. 1,

FIG. 5 is a diagrammatic view of a sewing machine installation in which this invention may be used advantageously,

FIG. 6 is a circuit diagram illustrating an electrical control circuit which may be used in the sewing machine installation of FIG. 5 to operate the thread wiper of this invention and,

3,448,708 Patented June 10, 1969 FIG. 7 is a diagrammatic view showing the relationship between a sewing machine loop taker and the elements of a sewing thread trimming device which may be used advantageously.

Detailed description of the invention The present invention as shown in FIG. 1 is illustrated as embodied on a two-needle lockstitch sewing machine, indicated generally at 10, having a frame including a work supporting bed 11, over which is supported a bracket arm 12, terminating in a sewing head 13. Supported for endwise reciprocation in the sewing head 13 is a needle-bar 14 having a needle clamp at the lower end in which is secured two needles 16 and 17 spaced relatively to each other lengthwise of the bed. Also carried for vertical movement in the sewing head 13 is a spring depressed presser-bar 18 carrying at its lower end a conventional presser foot 19. In the bed and cooperating with the needles 16 and 17 to form stitches may be a pair of rotating books (not shown) of the type described in United States Patent No. 2,763,226, Sept. 18, 1956 to G. Goebel,

to which reference may be had for a complete description thereof.

Extending from the back of the bracket arm 12 are two threaded mounting studs 21, each accommodating a pair of lock nuts 22-22 for securing thereon a support plate 23. The support plate 23 being so formed as to enclose as Well as to support a thread wiper driving mechanism indicated generally at 20. Secured to the inside of the support plate 23 by screws 2424 is an electrically operated solenoid 25, preferably mounted to have its armature 26 travel substantially horizontal, i.e., perpendicular to the axis of the needle bar 14. Connected to the solenoid armature 26, by a pin 27 is one arm 28 of a bell crank lever 29. The bell crank lever has a hole 30 accommodating a shouldered fulcrum screw 31 which is secured to the support plate by a nut 32. The bell crank arm 28 is slotted as at 34 to embrace the pin 27 of the solenoid armature. The other arm 35 of the bell crank lever 29 is bifurcated as at 36 and embraces a shouldered driving stud 37 for the thread wipers.

. One end of a coil spring 38 is anchored to a screw 38 secured in a threaded hole 40 in the support plate 23. The other end of the coil spring 38 is hooked on a screw 41 which may be threaded selectively into one of the threaded holes 42 in the bell crank arm 35. The coil spring 38 biases the bell crank lever 29 in counter clockwise direction as viewed in FIG. 1 against a stop lug 43 formed as part of the support plate 23. Another stop lug 44 on the support plate limits the clockwise motion, as viewed in FIG. 1, of the bell crank lever 29 when the solenoid 25 is energized.

Mounted in the sewing head 13 is a presser-bar bushing 50 (shown in FIG. 4.) which bushing as is conventional in a sewing machine construction, guides the presser-bar for endwise movement relatively to the sewing machine head. The conventional presser-bar bushing 50 is utilized to support the thread wiping elements of this invention by means of a mounting block 51 formed with a presserbar bushing by a clamping screw 53. The mounting block 50 is formed with two semi-cylindrical grooves 54 one on each side of the presser-bar accommodating aperture 52. Passing through a hole 55 in a clamping bar 56 is a screw 57 accommodated in a tapped hole 58 in the mounting block 51. The clamping bar 56 is formed with two semicylindrical grooves 59 spaced similarly with the grooves 54 of the mounting block 51 so that when assembled, the grooves 54 and 59 of the members 51 and 56 serve to accommodate and to clamp two tubes 60L and 60R securely to the presser-bar bushing which is fixed in the sewing machine head. Preferably the tubes 60L and 60R extend upwardly from the block 51 in substantially straight parallel relation. Downward from said mount block 51 the tubes 60L and 60R are each bent as at 61L and 61R to converge each toward a respective one of the needles 16 and 17. Slidably constrained within the tubes 60L and 60R are two thread wiper fingers 62L and 62R respective ly. The fingers are preferably made of a fiat springy material and each is formed at the lower free extremity with a point 63L and 63R and at one side with a barb 64L and 64R.

Extending within the upper straight portions of the tubes 60L and 60R are cylindrical rods 65L and 65R. The rods may be slotted as at 66L and 66R each to accommodate one of the thread wiper spring fingers 62L and 62R which may be secured to the respective rods as by pins 67L an 67R.

Beyond the upper extremity of the tubes 60L and 60R, the cylindrical rods 65L and 65R are secured in parallel holes 70 in a bar 71 as by set screws 72. Between the holes 70, the bar 71 is formed with a tapped hole 73 adapted to accommodate the shouldered driving stud 37 previously described.

Considering the assembled thread wiper mechanism the spring 38 will elevate the bell crank arm 35 against the stop lug 43 when the solenoid 25 is deenergized and as illustrated in FIGS. 1 and 3, the extremities 63L and 63R of the spring fingers 62L and 62R will be retracted within the tubes 60L and 60R. When the solenoid 25 is energized, the armature 26 will be drawn to the left as viewed in FIG. 4 depressing the bell crank arm 35 against the stop lug 44 and shifting the spring fingers 62L and 62R downwardly and beyond the lower extremities of the tubes 60L and 60R.

Preferably the spring fingers are formed initially straight and when retracted as illustrated in FIG. 3 are not elevated beyond the bent portions 61L and 61R of the tubes. The barbs 64L and 64R which are preferably formed on the outer sides of the spring fingers are therefore urged against the tube sidewalls when the spring fingers are retracted and when the spring fingers are extended as illustrated in FIG. 2, the bent portions of the tubes serve to deflect the spring fingers to move in a path in which the barb 64L and 64R traverse the paths of reciprocation of the respective needles 16 and 17 so that the barb will hook over and engage thread links extending from the needles to the work being stitched. When the fingers are retracted, the barbs will draw the engaged thread links upwardly into the tubes and because the barbs will be biased against the tube sidewalls, the engaged threads will not readily step from the barbs the thread will however, be free to move lengthwise about the barb and thus when sewing is commenced after a thread wiping operation, the thread ends which have been drawn into and detained in the tubes will draw freely into the work.

It will be understood that the thread wiper of this invention may be used in any sewing machine installation in which a thread wiper had been previously used in the prior art. The solenoid 25 may be energized by manual closure of a control switch (not shown) or the control switch for the solenoid may be closed by the operation of a element of the sewing machine such as for instance upon operation of either the resser-foot lifting levers 80 or 81 shown in FIG. 1.

The thread Wiper of this invention is particularly advantageous however, when used in combination with a device which automatically cuts the sewing threads at the completion of a sewing operation. Reference is made to my United States patent application Ser. No. 562,576, filed July 5, 1966, now abandoned, for a detailed description of such thread trimming device. Only such description of such thread trimming device will be made here with particular reference to FIGS. 5, 6 and 7 of the drawings as will provide an understanding of the manner in which the above described thread wiper cooperates with the thread trimming device. Where possible, the

4 reference notation used in FIGS. 5, 6 and 7 will conform with that used in my above referenced patent application Ser. No. 562,576.

As illustrated in FIG. 5, the sewing machine 11, 12, 13 is fitted with a clutch-timer unit CT by which drive belts B1 or B2 may be selectively brought into driving relationship with the sewing machine. The belt B1 is driven by a conventional clutch brake controlled transmitter M1 and the belt B2 is driven by an auxiliary slow speed m0- tor M2. The clutch-timer unit also includes contacts monitoring the needle up and needle down condition of the sewing machine. The transmitter clutch brake is controlled by a treadle T and the connection therebetween influence switches S1 and S3 which by way of the control system cause the clutch-timer unit CT to bring the belt B1 into driving relationship with the sewing machine when the transmitter is clutched into driving condition by toeing of the treadle T thus to drive the sewing machine during normal stitching operation. When the treadle is heeled, however, switches S1 and S3 serve by way of the control system to cause the clutch timer unit CT first to cause the belt B2 to be brought into driving relationship with the sewing machine and thereafter to stop the sewing machine in the needle down position.

When the sewing machine has been stopped in the needle down position by the operation of the control system, closure of a switch S2 by the operator will initiate operation of the thread trimming device.

The operative elements of the thread trimming device are illustrated diagrammatically in FIG. 7. A sewing machine loop taker such as one of the loop takers which may be provided to cooperate with the needles 16 and 17 shown in FIGS. 1, 2 and 3, is indicated at 100. The looptaker is formed with a needle thread seizing beak 101 which moves relatively to the path of needle reciprocation indicated at 102 to seize and carry loops of needle thread about a bobbin case 103 in the loop taker during sewing. In sewing, therefore, loops of needle thread are carried by the loop taker about a bobbin thread 104 extending from the bobbin case toward the path of needle reciprocation and into the seam being formed in the work. When the sewing machine occupies needle down position, the loop taker beak will be approaching the path of needle reciprocation to seize the needle thread as shown in FIG. 7.

The thread trimming device includes a thread catching finger 105 shiftable by a solenoid SOL2 toward the loo taker to engage the bobbin thread 104 and also to Wait for and engage the needle thread which will be seized and manipulated by additional rotation of the loop taker 100.

The control system in response to closure of the switch S2 will energize the solenoid SOL2 and thus, by way of the clutch-timer unit will engage the belt B2 to drive the sewing machine into needle up position thus causing the additional rotation of the loop taker.

In the needle up position of the sewing machine, the thread catching finger 105 with the needle and bobbin threads engaged thereon will be returned drawing out these threads into the path of a thread cutting knife 106' which is actuated by a solenoid SOL1 energized by the control system after the sewing machine has reached needle up position.

Preferably the solenoid SOL25 for the thread wiper should be energized slightly in advance of the knife solenoid SOL1 so that the barbs of the thread wipers can pass across the needle threads which are taut before they are severed thus to insure engagement of threads by the barbs.

This desired sequence of operation of solenoid 25 slightly before operation of solenoid SOL1 may be accomplished as illustrated in FIG. 6 by the provision of contacts R3-C7 for operating solenoid 25 by the discharge of capacitor CAPl immediately upon deenergization of a relay R3 when the needle up position effects opening of the timer contacts S8. A slightly delayed operation of the solenoid SOLl is elfected by the provision of a separate relay R4 which is also energized by the discharge of capacitor CAPl. The solenoid SOLl will be energized by the discharge of capacitor CAP3 in response to closing of contacts R4-C1 upon energization of relay R4. It will be appreciated that other known circuits for accomplishing such sequential operation of the solenoids SOL25 and SOLl might be utilized.

When combined with a needle positioner and thread trimmer as described above, the operation of the thread wiper of this invention is entirely automatic and does not require any operator attention. The thread wiper will serve to remove the needle thread ends from the work immediately at the conclusion of the seam formation and before the operator can shift the work, and the thread ends will be held above the Work and in the tubes as illustrated in FIG. 3 so that inadvertent catching and distention of the threads by the operator during removal and replacement of work under the presser foot will be minimized. At the succeeding start of stitching, the thread wiper will hold the needle thread ends away from the needle path but free to be drawn from the tubes as stitching commences, thus providing for a clean snarl free start of the next stitched seam.

Having thus set forth the nature of this invention, What I claim herein is:

1. A needle thread wiping device for a sewing machine having a frame, and a thread carrying needle supported in said frame for reciprocation in an endwise path, said thread wiping device comprising a guide tube carried by said frame and having a predetermined'lengthwise configuration and a termination remote from said needle path, an elongate resilient thread wiping finger shiftably supported in said guide tube and having a portion movaable beyond the termination of said guide tube, said thread wiping finger having a normal lengthwise configuration dilferent from the lengthwise configuration of said tube, said predetermined lengthwise configuration of said guide tube changing said normal configuration of said finger and constraining that portion of said thread wiping finger as it is moved beyond the termination of said guide tube to traverse said path of needle reciprocation, a thread engaging means on said portion of said thread wiping finger, and means carried on said sewing machine frame for moving said thread wiping finger.

2. A needle thread wiping device as set forth in claim 1 in which said tube includes a substantially straight upper portion supported on said sewing machine frame and a lower bent portion.

3. The combination comprising a sewing machine having a frame including a work support, and a thread carrying needle supported on said frame for reciprocation in an endwise path traverse said work support, needle positioning means automatically efiective to stop said sewing machine with said needle extending through said work support and automatically operative thereafter for positioning said needle above said work support, a needle thread wiping device carried on said sewing machine frame, needle thread trimming mechanism associated with said sewing machine including a thread severing element arranged beneath said work support, and means responsive to operation of said positioning means for operating said thread wiping device and said thread severing element. 7

References Cited UNITED STATES PATENTS 1,269,710 6/1918 Hill 112---252 1,332,683 3/1920 Ray 112252 1,336,808 4/1920 Barron et a1. 112-252 1,358,847 11/1920 Hill 112252 2,914,010 11/1960 Cohen 112252 RICHARD J. SCANLAN, JR., Primary Examiner.

US. Cl. X.R. 112-67 

